This invention relates to an automation system for nuclear power plants, and more particularly to an automation system for nuclear power plants, which is suitable for application to boiling water type nuclear power generation plants and which becomes effective when the plant condition deviates from the normal operation range.
Starting of the nuclear power plant or adjusting the control rod pattern have been done according to an operation plan prepared beforehand. If the nuclear power generation plant is in the state as prearranged in the operation plan, there is no problem in operating the plant according to the operation plan. However, when the process quantities such as reactor power, core flow rate, neutron flux, core temperature, core performance which is a thermal characteristic of the reactor core or the operating condition of the equipment such as the pump and control rods differs from the plan, the operators of the plant usually make various decision-making operations.
In the load follow-up operation of the boiling water reactor (BWR), a technique of preventing the core from deviating from the operational limit condition or a technique regarding the remedial actions for the deviation is disclosed in JP-A-57-189097 entitled "Operation Control System of Boiling Water Reactor." This Japanese patent publication describes with regard to the load follow-up operation (1) when a decision is made that data used for calculating the core performance (core flow rate, core pressure, core temperature, neutron flux, etc.) or the calculated values of core performance deviate from the operational limit condition, a method for avoiding the deviation from the operational limit condition is considered (the load follow-up plan is revised) and (2) when the above-mentioned plant data or the calculated values of core performance have deviated from the operational limit condition, the recirculation flow rate control system is blocked, and then, an operation plan to bring the above-mentioned data or the like back within the limit condition or an operation plan after the data has returned within the limit condition is prepared. Blocking the recirculation flow rate control system is meant here to maintain the current condition without changing the recirculation flow rate (more specifically, not to change the set value of the recirculation pump speed or the recirculation flow rate).